Cayin SMP-PRO4 Посібник з відтворення - Сторінка 3

Переглянути онлайн або завантажити pdf Посібник з відтворення для Медіаплеєр Cayin SMP-PRO4. Cayin SMP-PRO4 12 сторінок. Smp series

CAYIN SMP Player Video Playback Guide

players to deal with various codecs.

Please refer to the following sections for a more detailed introduction and the codec

information supported by CAYIN's SMP player.



Bit Rate (bps):

Video is usually saved after compression. If we divide compressed data size (in bit/s) by

video length (in seconds), we will get bit rate (bits per second or bps) for this video. Take a

30‐second video file, for example. The file size is 6M bytes (=48M bits). If we don't count

the data size occupied by the file header and audio, we can say that the bit rate of this

video file is about 1.6M bps (48/30=1.6).

If we use the same compression method (codec), usually the higher the bit rate is, the

greater the video quality will be, as well as higher decoding loading. According to each

different codec, the number of bits (data amount) can be different for each frame or

video clip within a video. Thus, video compression methods can be divided into two

categories: CBR (constant bit rate) and VBR (variable bit rate). For CBR, the compression

rate and data amount for each clip is relatively the same. On the contrary, the bit rate of

VBR video will be adjusted based on the actual video content. Higher bit rate is really

applied to dynamic video clips, while lower bit rate is used for more static ones. The latest

codecs and video mostly adopt VBR as the compression method.

Since VBR will use different compression rates for different video clips, the bit rate for

VBR method is usually categorized into two types: average bit rate and peak bit rate. For

the average bit rate, we divide the total video data size by the total playback length (time)

to get an average number. However, peak bit rate refers to the maximum bit rate within a

certain period of the video. As previously mentioned, the average bit rate of the 6M bytes

video file is only 1.6M bps. However, during some period of time, the peak bit rate could

be 8M bps. Under the circumstances, if a media player can only support a bit rate of 5M

bps, you may see the video playing sluggishly during the 8M bps segment.